Prospective serial proton MR spectroscopic assessment of response to tamoxifen for recurrent malignant glioma.

OBJECTIVE: Early prediction of imminent failure during chemotherapy for malignant glioma has the potential to guide proactive alterations in treatment before frank tumor progression. We prospectively followed patients with recurrent malignant glioma receiving tamoxifen chemotherapy using proton magnetic resonance spectroscopic imaging ((1)H-MRSI) to identify intratumoral metabolic changes preceding clinical and radiological failure. METHODS: We performed serial (1)H-MRSI examinations to assess intratumoral metabolite intensities in 16 patients receiving high-dose oral tamoxifen monotherapy for recurrent malignant glioma (WHO grade III or IV) as part of a phase II clinical trial. Patients were followed until treatment failure, death, or trial termination. RESULTS: Patients were officially classified as responders (7 patients) or non-responders (9 patients) 8 weeks into treatment. At 8 weeks, responders and non-responders had different intratumoral intensities across all measured metabolites except choline. Beyond 8 weeks, metabolite intensities remained stable in all responders, but changed again with approaching disease progression. Choline, lipid, choline/NAA, and lactate/NAA were significantly elevated (P < 0.02), while creatine (P < 0.04) was significantly reduced, compared to stabilized levels on average 4 weeks prior to failure. Lactate was significantly elevated (P = 0.036) fully 8 weeks prior to failure. In one patient who was still responding to tamoxifen at the conclusion of the trial, metabolite intensities never deviated from 8-week levels for the duration of follow-up. CONCLUSIONS: Characteristic global intratumoral metabolic changes, detectable on serial (1)H-MRSI studies, occur in response to chemotherapy for malignant glioma and may predict imminent treatment failure before actual clinical and radiological disease progression.

Recording of ventral posterior lateral thalamus neuron response to contact heat evoked potential in patient with neurogenic pain.

Microrecording of single unit response to contact heat-evoked potential (CHEP) were performed in right ventral posterior lateral (VPL) thalamus during deep brain stimulation (DBS) surgery in a patient with chronic neurogenic pain. In our patient, neurons (n = 10) recorded in the ventral thalamus fired at a higher rate of 40 Hz compared to neurons recorded in Parkinsonian patients (24 Hz). Contact heat was applied by a fast heating and cooling probe of 5 cm2 area on the dermatome C6 territory of the left hand. One out of four thalamic cells located in the VPL responded repetitively 325 ms after the peak temperature was reached with a burst of action potential, suggesting A-delta fibre activation. This observation supports the use of CHEP for mapping nociceptive neurons location during DBS surgery for intractable pain.

Quality index for the quantification of the information recorded along standard microelectrode tracks to the subthalamic nucleus in parkinsonian patients.

OBJECTIVE: To quantify the usefulness of the neuronal activity recorded on a standard microelectrode track to the subthalamic nucleus (STN) for the determination of the transition between the thalamus and the STN. METHODS: The study is based on analysis of 689 extracelullar single units recorded on 70 tracks passing through the thalamus and the STN. Using four neuron parameters that were correlated with electrode depth, a quality index (QI) for each track was computed and compared with the subjective assessment by the electrophysiologist of the track quality. RESULTS: Subjectively, the transition between the thalamus and the STN was detected in 49 tracks (usual track) and not detected on 21 tracks (unusual tracks). Objectively, spike frequency, cell burst index (BI), signal relative root mean square (RMS) and spike relative amplitude were correlated with electrode depth and used to compute track QI. The average QI index of usual and unusual tracks was 0.25 +/- 0.9 and 0.85 +/- 0.15 (mean +/- confidence interval at P < 0.001), respectively. In 20 patients, QI correlates with post-operative measurement of electrode length in the STN. CONCLUSION: These results demonstrate that simple statistical analysis taking into account the variation of single-unit characteristics with electrode depth can discriminate between useful and useless tracks for the determination of the STN localisation.

Subthalamic nucleus deep brain stimulation for Parkinson's disease: magnetic resonance imaging targeting using visible anatomical landmarks.

BACKGROUND: The aim of the present study was to validate a magnetic resonance imaging (MRI) visual procedure to target the subthalamic nucleus (STN) based on surrounding anatomical landmarks. METHODS: 31 consecutive bilaterally implanted parkinsonian patients were included in this study. After identification of the anterior commissure (AC), posterior commissure (PC) and midcommissural point on a three-dimensional T1-weighted sequence, inversion recovery (IR) T2-weighted coronal slices were performed orthogonal to the AC-PC line. On the slice showing the anterior pole of the red nucleus (RN), the target was placed in the inferolateral portion of the subthalamic zone, limited superiorly by the thalamus, laterally by the internal capsule, inferiorly by the substantia nigra and medially by the midline. The distribution of the targets was analyzed in the AC-PC referential. RESULTS: The mean target coordinates were as follows: anteroposterior (AP) = -2.54 mm (+/-1.37 mm), lateral (LAT) = 12.03 mm (+/-0.91 mm) and vertical (VERT) = -6.10 mm (+/-1.52 mm) for the right side, and AP = -2.65 mm (+/-1.36 mm), LAT = -11.97 mm (+/-1.30 mm) and VERT = -5.89 mm (+/-1.52 mm) for the left side. They projected in the inferior portion of the STN on the Schaltenbrand and Wahren atlas [Stuttgart, Thieme, 1977]. CONCLUSION: Identification of the anterior pole of the RN and the subthalamic zone on coronal IR T2-weighted MRI performed orthogonal to the AC-PC line provides a precise visual procedure to target the STN.

Electrophysiological localization of the subthalamic nucleus in parkinsonian patients.

Deep brain stimulation of the subthalamic nucleus (STN) is becoming the procedure of choice to reduce symptoms of Parkinson's disease such as rigidity, akinesia and tremor. We present here a series of electrophysiological recordings performed in 34 patients along a standardized electrode trajectory. Neuronal activity along the trajectory consists of a first heterogeneous population of thalamic cells with a mean frequency of 24.8+/-1.4 Hz followed by a silent zone and a second population of STN neurones with a significantly higher spiking frequency (P<0.001) of 42.3+/-1.8 Hz. This study confirms previous findings and suggests that rapid measurement of neuronal spiking frequency and burst index is sufficient to determine precisely the vertical position of the STN.

[Cystic adenocarcinomas of the lacrymal gland]. / Les adénocarcinomes kystiques de la glande lacrymale.

UNLABELLED: Adenoid cystic carcinoma of the lacrimal gland. BACKGROUND: Adenoid cystic carcinoma is the most frequent epithelial tumour of the lacrimal gland. It represents 1.6 % of the orbital tumours. The aim of this study is to present a series of such patients who were followed up in our clinic and to discuss their clinical management in order to achieve a better life prognosis. MATERIALS AND METHODS: The cases we followed up in our department were presented, the treatment modalities were discussed, and conclusions were drawn. RESULTS: Six patients with this pathology were examined, 3 men and 3 women, aged 31 to 69 years. A large excision was performed in 5 patients (exenteration alone or extended exenteration with complementary radiotherapy) and in 1 patient with excision of the tumour followed by radiotherapy. One patient died due to carcinoma six years after the first surgery. The median follow-up period of our cases is 25 months. CONCLUSION: Adenoid cystic carcinoma of the lacrimal gland is a malignant tumour with a reserved prognosis. Various treatments were proposed to improve the mortality rate of the disease. At present radical surgery with or without complementary therapy seems to give the best chances of healing, at least with short or mid-term follow-up.